Art. 2. The armed force of a State includes: 1. The army properly so called, including the militia; 2. The national guards, landsturm, free corps, and other bodies which fulfil the three following conditions: (a) That they are under the direction of a responsible chief; (b) That they must have a uniform, or a fixed distinctive emblem recognizable at a distance, and worn by individuals composing such corps; (c) That they carry arms openly; 3. The crews of men-of-war and other military boats; 4. The inhabitants of non-occupied territory, who, on the approach of the enemy, take up arms spontaneously and openly to resist the invading troops, even if they have not had time to organize themselves.